This invention relates to a binding for fiber bundles, a method for producing the binding and an apparatus for carrying out the method.
1. Field of the Invention
The term "fiber bundle" as used herein indicates a bundle of fibers, a yarn, or a ply yarn, a twine or a rope or a similar stretched structure of fibers or filaments which are brought together, in which both vegetable and animal, as well as synthetic, basic materials can be included. In the broadest sense, the invention relates particularly to the field of textiles and generally to the products of the textile industry; however, it is not restricted to this field.
2. Description of the Prior Art
The problem frequently arises, in the relevant manufacturing and processing industry, of binding two or more fiber bundles together. This problem has been solved exclusively for a long time by tying or knotting the free ends of the fiber bundles which are to be bound together in a manual or mechanical manner. This solution to the problem has proved to be extremely expedient and economical for many purposes. However, it should be appreciated that apparatus for mechanically joining such bundles with knots, that is, so-called automatic knotters or knotting apparatus, are relatively complicated mechanical devices, which are therefore also relatively expensive.
Binding fiber bundles, achieved by knotting, has the additional disadvantage for many application purposes that the knot which is produced necessarily has a much larger cross section than the individual fiber bundle itself. During the further processing of the knotted fiber bundle, for example, in weaving or knitting, this fact can have a detrimental effect and can cause the fibers to break or can cause other disturbances during production. Thus, suggestions have repeatedly been made to accomplish the binding of fiber material in a manner other than by knotting.
A process for splicing fibers by using a knotting device comprising an air nozzle is known from German Offenlegungsschrift No. 2,865,514. In such a device, one end of both the spun yarns or fibers is introduced from one side into a fiber inlet in the air nozzle of the knotting device and the other end is introduced into the inlet from the other side. By this means, both fibers are joined together and then at least one of the fibers is slightly loosened before or at the same time as the air is blown out onto the fibers.
Another process is known from German Offenlegungsschrift No. 2,750,913 for binding textile fibers by means of an apparatus comprising a whirling chamber having a longitudinal groove for inserting and removing the fibers to be bound. In this arrangement, the fibers, which are inserted so that they are lying next to each other and are held by a fiber clamping apparatus located outside the whirling chamber, are whirled together by the admission of compressed air and are bound together in this manner. The textile fibers which are to be bound are inserted into the whirling chamber so that they wind around both the edges of the openings of the whirling chamber. In this way, the textile fibers are subsequently whirled when they are slack and lying without tensile stress in the whirling chamber, being secured, however, by the fiber clamping apparatus, and the fiber tension is slackened only to such an extent that the false twist which is imposed while the textile fibers are being whirled and the shortening of the fiber length, being determined thereby, arranges the textile fibers against the edges of the opening of the whirling chamber.
Finally, Offenlegungsschrift No. 1,962,477 describes an apparatus for splicing yarns by using a rotating drum which is mounted on a casing element, the drum having a yarn groove running through the axis thereof for accommodating the overlapping ends of yarns to be spliced, which are arranged in adjacent parallel relationship to each other. The apparatus also uses devices for rotating the drum about the overlapping ends of the yarn to be spliced and devices carried by the drum for accommodating a source of winding fibers. A fiber groove is disposed in this drum adjacent to an outlet and is positioned radially with respect to the axis of this drum, whereby a larger moment is exerted on the winding fiber (which runs through the fiber groove) during operation when the fiber groove is rotated about the yarn.
Methods and apparatus in which a fluid, for example, compressed air, has to be blown into a whirling chamber, are complicated and troublesome, particularly because the fluid has to be admitted. They also form relatively-long binding points, which tend to produce difficulties during the processing of the bound fiber bundles mainly because of their length, but also because of their structure.
By using the solution to the problem proposed in the aforesaid German Offenlegungsschrift No. 1,962,477, relatively-firm bindings are, indeed, produced and the diameter of the binding point can be kept sufficiently small to facilitate the further processing thereof. However, in this solution, it is a fact that the binding point becomes relatively taut with regard to a normal fiber bundle and can thereby lead to difficulties in processing. The subsequent detachment of the winding yarn also necessitates an additional operating cycle to produce the product manufactured by use of bound yarns of this type. Difficulties can also arise in procuring suitable winding yarns for all possible fiber bundles to be processed.